(DrEddyClinic News) Females exposed to DDT in the womb may be more likely to suffer from obesity and diabetes in middle age, according to a study conducted by researchers from the University of California-Davis and Mount Sinai School of Medicine, funded by the National Institute of Environmental Health Sciences and published in the journal PLOS ONE.

DDT is an insecticide that became popular worldwide in the late 1940s. It was banned in the United States in 1972, due to evidence of toxicity and reproductive harm. It has also been shown to accumulate in the environment and resist decomposition. In spite of having been banned more than 40 years ago, vast quantities of DDT can still be found in areas such as the San Francisco Bay canal, where the chemical http://bit.ly/chemical-toxic-metal-cleanse-kit remains part of the oceanic food web and contaminates fish that are consumed by humans.

DDT is also still used in numerous countries outside the United States, including to kill malaria-carrying mosquitoes in India and South Africa.

Females especially vulnerable

The researchers exposed mice in the laboratory to doses of DDT equivalent to those that would have been experienced by pregnant women in the United States 50 years ago, or that pregnant women might be exposed to in India or South Africa today. They then observed the offspring of these exposed mice.

The researchers found that female mice who had been exposed to DDT in the womb showed subtle differences from non-exposed females as early as young adulthood: a slightly lower core temperature, a tendency to burn fewer calories for the same amount of exercise, and slightly higher weight and body fat proportion. By about six months of age, the DDT-exposed females began to exhibit hampered glucose tolerance and higher levels of fasting glucose, insulin and blood lipids.

At six months of age, all the mice were put on a high-fat diet for 12 weeks. DDT-exposed females developed significantly more symptoms of metabolic syndrome than non-exposed females.

Metabolic syndrome refers to a cluster of risk factors for diabetes http://www.dreddyclinic.com/forum/viewforum.php?f=29 and cardiovascular disease. The symptoms exhibited by the mice included glucose intolerance, insulin sensitivity and high cholesterol, which are also risk factors for liver disease.

Although male mice exposed to DDT http://www.dreddyclinic.com/forum/viewtopic.php?f=15&t=34734 in utero showed slightly impaired glucose tolerance compared to other males, they did not exhibit any of the other symptoms seen in females. The reason for this difference is not known, but it may be connected to DDT's well documented hormone (endocrine) disrupting effects.

Exposure affects four generations or more

The researchers suggested that the susceptibility to metabolic syndrome in female mice may have stemmed from their hampered ability to regulate their body temperature, indicated by lower-than-normal core temperatures.

"As mammals, we have to regulate our body temperature in order to live," lead author Michele La Merrill said. "We found that DDT reduced female mice's ability to generate heat. If you're not generating as much heat as the next guy, instead of burning calories, you're storing them."

The worst symptoms in the mice did not emerge until middle age, which has troubling implications for health in the United States.

"The women and men this study is most applicable to in the United States are currently at the age when they're more likely to develop metabolic syndrome, because these are diseases of middle- to late adulthood," La Merrill said.

"Here is an ancestral exposure in your great-grandmother, which is passed on to you and you're going to pass on to your grandchildren," said Michael Skinner, PhD, of Washington State University, lead researcher on a multi-generational study recently published in BMC Medicine.